poppet valve

[jrunger]

HI,<br /><br />I have been reading posts about implellers/thermostats and noticed reference to poppet valves. Would someone mind telling me a little bit about this valve -- first I have learned of it. Where is it, what does it do, should it be replaced once in a while, etc. Thanks in advance.

 

[imported_scott_m]

Re: poppet valve

On my 135 V-6, the poppet valve is on the lower starboard side of the block. I have to remove the ignition boxes to get good access to it. The purpose of the valve is to hold water in the block at lower RPMs to ensure adequate contact time with the block (heat transfer). At higher RPM's (about 3000 I think), the valve will 'pop' open based on water pressure to relieve this extra water in the block to keep the temp cool. If you are running hot at idle, it's likely stuck open, and hot at higher RPM means it is likely stuck closed. I'm not sure about the maint schedule, nor when mine had ever been done but it was a source of overheating for me earlier this year. I boat in salt water now and it was pretty nasty inside the housing. ALso the diaphram was pretty weak. It's about a 10 dollar part and 3-4 bolts to change it out.

 

[Laddies]

Re: poppet valve

The popet valve is a pressure relief vanloe in the cooling system that opens at higher RPM to let the system cool. it is a plastic plunger with a sring holding it cooled on one end and a diaphram to open it on the other. In most cases on the head (water jacket cover) but on some engines on the exhaust cover

 

[jrunger]

Re: poppet valve

thank you ---- helps me understand it. At the moment I do not seem to be having any problems --- I was just wondering about it ---- however ---- is it something that should be changed from time to time?

 

[KCLOST]

Re: poppet valve

These don't nomally fail (except for the diapram possibly tearing or in corrosive water the spring desinigrating) It's more the case of the poppet assembly getting clogged with debri that will either cause it to stick open or fail to open at all.]<br />It is very easy to remove and clean... Just keep track of all the components and you should replace the gaskets for the inner and outer plates if you take it apart...